Method of resurfacing old concrete roadways



April 29', 1924' B. MCCAFFREY METHOD OF. REsURFAcIN OLD CONCRETE ROADWAYS Filed July 25, 1923 Jw'eep and clear, and waJh'roadway Jaffame wii/Z-r zapiM r any olfigv' yr'ecu e Grail remover.

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umrao STA res PATENT OFFICE.

BERTIN McCAFFREY, 0E WEST HOBO'KEN, NEW JERSEY.

METHOD OF RESURFACING OLD CONCRETE ROADWAYS.

Application filed July 25, 1923 Serial No. 653,806.

T 0 all whom it may concern:

Be it known that I, BERTIN MCCAF'FREY, a citizen of the United States, residing at West Hoboken, in the county of Hudson and State of New Jersey, have invented certain new and useful Improvements in Methods of Resurfacing Old Concrete Roadways, of which the following .is a specification.

' My invention is a method of resurfacing old concrete roadways.

An important-object of the invention is to provide a method of the above mentioned character, whereby old concrete roadways, when worn, may be restored by providing the same with an asphalt surface coat, of a proper thickness, such coat being securely anchored 'or bonded to the old concrete roa dway, in a manner-to prevent separation, creeping or. s1ipping.

A 'furtherob'ject of the invention is to provide a ,method of the above mentioned character, adapted for applying the asphalt surface coat to a concrete roadway having no curb.

Other objects and advantages of the in- I vention will be apparent during the course 'of the following description. Z In the accompanying drawings, forming a part of. this specification, and in which like numerals are employed to designate like parts throughout the same,

F1gure 1 1s a vertical transverse section through a-ooncrete roadway, illustrating the j cleaning of the roadway,

" Figure 2 .is a similar view illustrating the I checkering or marking of the concrete roadway and the applying of the asphaltic paint. Figure 3 is a plan view of the same, and, Figure 4 is a transverse vertical section throng}, the pleted roa way, showing the application of the asphalt surface coat.

In accordance with my method, the old concrete roadway 5 has its surface mechanically cleaned, as by sweeping, for removing therefrom substantially all of the solid foreign matter, such as dirt, dust, etc. It is preferred that the sweeping be done thoroughly, so that substantially all of the solid-foreign matter may be removed, or as much removed as is practicable After the sweeping or cleaning of the solid foreign matter has been completed,

the next step in the method is to wash the surface of the concrete roadway, with-a liquid which will remove oils and greases. I preferably employ for this purpose naphtha, or any other grease or oil remover; This washing may be effected by means of vbrooms, mops, or by any manual or mechanical means, desired. The washing 1s preferably done m a thorough manner for re-' moving. substantially all traces of the oil or grease from the concrete roadway, or as much thereof as is practicable.

The old concrete roadway thus thoroughly cleaned of all oils or greases, next has its surface roughened. This is preferably ac-. complished by checkering, marking or grooving the surface, as indicated at 6, by using a scarifier, or bymeans of any other hand method or mechanical device, which may be practicable. 1 The ch'eckering or marking consists in forming indentations in the face of the concrete roadway, which indentations may extend over substantially the entire surface of the roadway, or a part thereof. The checkering or marking of the roadway is preferably distributed uniformly through the entire area of the same, but the fineness of the checkering or marking may vary somewhat, as may be found advantageous. It is ordinarily preferred that phalti paint coat, which is applied to the.

entire surface thereof, by means of a brush or any other suitable means. This asphaltic paint coat, at atmospheric temperature, is of a heavy plastic consistency, and in order to apply the same to the concrete roadway,

it must be first heated so that it is rendered fluid. In this heated fluid condition-it may be splashed upon the roadway, or applied by means of a brush. The asphaltic paint may also be rendered fluid, without heating, by dissolving the same in a suitable amount of naphtha, which would then produce a fluid known in the trade as a cut back asphalt. This liquid may be applied witha brush or by splashing, or by any other suitable means. This asphaltic paint mixes with the asphalt in the asphalt surface coat, to be described, and leads the same into the crevices or .pores of the concrete. The function of this asphaltic paint coat is to ,aid in the adhesion of the asphalt surface coat, which is subseguently applied, so that the shoving or creeping of the asphalt surface coat is prevented.

After the concrete roadway is thus treated, and with the asphalt paint applied thereto, the next step in the method is the laying thereon of an asphalt surface coat 8, which preferably has the thickness of from of an inch to 1% inches.

The asphalt used in the asphalt surface coat shall be of any standard type or brand manufactured for paving purposes, and shall preferably have a penetration of from 40 to 60 under N0. 2 needle at 77 F.5 seconds, f) grams, and it is preferred that the penetration shall not vary outside of these limits, except when climatic conditions make it necessary to vary the same above these limits. The asphalt surface coat embodies mineral aggregates, and asphaltic or bituminous material. The mineral aggregate should preferably consist of broken stone, gravel, sand, or othersuitable material, so that the same may meet one of the following mesh compositions', in the finished coat or surface m1x-' ture:

Coat surface-mixture A.

Percentage of total mixture Mineral aggregate.

as laid.

Per cent.

Passing 200 mesh screens...

Percentage oi total mixture Mineral aggregate.

as laid Per cent.

and retained on 200 mesh 1 l l I l l I l l U u 10 u u u n u 40 u i: i u u u u u 10 u 'u n u 4 u Passing 200 mesh screens :4 80 u n N ocooseosen were re 000080 HMONNH ONOUIQN Goat surface mixture 0.

Bitumen 9.5 to 13.5 per cent.

Percentage of Mineral aggregate. total mixture as laid.

Per cent. 2 Passing 200 mesh. Not less than 10 80 10to35 50 4 to 35 40 4 to 4 to 20 20 4 to 12 10 2 to 12 8 f 0 to 5 Total passing 200; 11 and 80 mesh Notlcss than 25 50, and 15 to 30, 20and 10 l0to35 Coat surface mixture D.

Percentage of Mineral aggregate. total mixture as laid,

. Per cent. Retained by 10 mesh sieve None Passing 10 mesh sieve, retained by 40, mesh sieve. 101:0 35 u 4 u n i. u 80' u i 20 to i. so u .r u 200 u u Y 15 to 30 12 to 20 9 to 12.5

The asphalt surface coat also embodies a mineral filler, which is Portland cement, or

limestone dust filler. This mineral filler is added to the miX in a suitable per cent tobring the finest of themineral aggregate, stated for the purpose of illustration as passing 200 mesh screens, up to between the limits of the per cent stated, as may be desired. For instance, in the surface coat mix A if only 2 per cent of the mineral aggregate passes through the 200 mesh screens, then not less than'3 per cent or more than 9 per cent of the mineral filler-will be added.

The mineral aggregate shall beheated in the following manner, and the asphalt shall also be heated in a manner to be described. The mineral aggregate for the surface coat shall be heated, before entering the mixer, to between 225 and 350 F., in a revolving drier of any approved type, in which no flame shall be permitted to come in contact with the aggregate. uously agitated during the heating. This heated mineral aggregate is then conveyed to a suitable hopper which may be located- 'above a rotatable. mixer.

The desired amount of the mineral aggregate may be Withdrawn into the rotatable mixer, and then the fine mineral filler, passing the200 mesh screens, is introduced cold into the mixer with the mineral aggregate, in the suitable per cent. The asphalt or asphalt cement furnished for the surfacecoat shall be heated separately from the mineral ag gregate in approved receptacles so designed The aggregate shall be continshall be heated to the temperature directed from time to time between 250 and 350 F. This heated asphalt cement, which is now in a liquid condition, is now introduced-into the mixer with the mineral aggregate and mineral filler, and the entire mass is thoroughly agitated, until the same becomes homogeneous.

The mixing shall continue until every particle of the mineral aggregate and mineral filler is completely coated with the asphalt cement, anda uniform mixture has been obtained. The mass when discharged from the mixer retains a temperature' of from not more than 350 F. and not less than 225 F.

The asphalt surface coat, heated and prepared as above described shall be delivered from the mixer to the point of deposition in the pavement, in suitable trucks or wagons, provided with canvas covers for retaining the heat. As delivered to the point of applica tion to the roadway, the asphalt surface coat shall have a temperature of at least 225 F.

The material having a lower temperature than 225 F. shall not be laid in the surface coat. The asphalt surface coat mixture shall be immediatelyspread over the concrete roadway, by men experienced-1n such work, so

- that when rolled it shall have a thickness at no place less than 9; of an inch, or more than 11} inches, and shall be free from surface depressions and irregularities.

The asphalt surface coat, when placed as above described,- shall be rolled at .once,

the asphalt surface coatsticking to the rollpelled tandem or while the material is still warm and pliable,

the rolling beginning at the edges in the,

roadway and working toward the center. Suitable means shall be provided to prevent surface coat into the crevices, pores or the like of the concrete. Th1s action 15 also aided by the pressure of the rollers. The

result of the combined action of the several steps of the method, is the maximum binding action between the asphalt surface coat, and concrete roadway.

While it is believed that more satisfactory .results are obtainable by employing all of the methods of the invention, in the treatthe asphaltic paint coat. This paint coat serves to lead the asphalting of the roadway, yet it has been found that in some instances, the roughening of the cleaned roadway may be dispensed with, and some degree of success obtained. Also, it has been found that the coating. of the roughened roadway with the asphaltic'painte may be dispensed with,.-in some instances,

'with some degree of success.

While thedrawing shows thesurface of the concrete roadway checkered diagonally, it is obvious that the invention is in'no sense restricted to this method of checker ing, as the roadway may be roughened in any manner desired. The checkering may be arranged longitudinally, transversely, 01' in an irregular manner, if desired.

It is to be understood-that the form of my invention herewith shown and described, is to be taken-as a preferred example of the same, and that various changes in theorder of the steps of the method, and that equiva lent steps may be employed, without departing from the spirit of my invention, vor the scope of the subjoinedclaims.

Having thus described my invention, I claim: 1

'1. The method of effecting.a'closeibond or union between the surface-ofaan-old-or worn concrete roadway and an asphalt surface coat mixture to be appliedthereto,

so that the asphalt surface coat .mixture thus applied will not slip or creep, by sweeping the surface of the old. or worn concrete roadway for removing foreign solid material, washing such surface with a solvent of oil and grease to remove the same, roughening the cleaned surface thus treated, applying to theroughened cleaned surface an asphalt paint coat, applying to the surface thus, coated a heated asphalt. surface coat mixture embodying mineral aggregates coated with asphalt, and then rolling the asphaltc-oat surface mixture while it 1s compressible.

2. The method of effecting a close bond or union between the surface of an old "or worn concrete roadway and ari asphalt surface coat mixture to be applied thereto, so that the asphalt surface coat mixturethus applied will not slip or creep, by sweep- .ing the surface of the old or worn con-.

crete roadway for removing foreign solid material, cutting such surface for producing anchorindentations, applying to the surface thus treated a liquid adapted to serve as a binder for an asphalt surface coat mixture, applying to the coated surface a heated asphalt surface coat mixture, and rolling the asphalt surface coat mixture while it is compressible.

'3. The method of effecting a close bond or union between the surface of an old or worn concrete roadway and anasphalt surface coat mixture to be applied thereto,

so that the asphalt surface coat mixture thus applied will not slip or creep, by sweeping and washing the surface of the old or worn concrete roadway for the removal ofsolid matter and grease, roughening the,cleaned surface, applying to the roughened surface an asphalt paint coat binder, applying to the surface thus coated a heated asphalt surface coat mixture, and then rolling the asphalt coat surface mixture while it is compressible.

4. The method of effecting a close bond or union between the surface of --an.old or worn concrete roadway and an asphalt surface coat mixture to be applied, thereto, so that the asphalt surface coat mixture thus applied will not slip or creep, by cleaning the surface of the old or worn con-- crete roadway to remove foreignmatter, roughening the. cleaned surface, forming longitudinal channelsnear the outer edges of the roadway, applying to the surface of the roadwaythus treated. a. heated, asphalt surface coat mixture, and then rolling the asphalt surface coat mixture while compressible whereby it becomes securely anch'ored'within the roughened portions of the surface and the channels.

5. The method of effecting a close bond or union between the surface of an old or worn concrete roadway and an asphalt surface coat mixture to be applied thereto,

so that the asphalt surface coat. mixture thus applied will not slip or creep, by sweeping and washing the surface of the old or worn concrete roadway for removing solid matchannels near the longitudinal outer edges of the roadway, applying to the surface thus treated a heated asphalt surface coat mixture, and then rolling the asphalt surface coat mixture. l

, ter and grease or oil, cutting anchor indentations in such surface, forming longitudlnal 6. The method of effecting a close bond or union between the surface of an old or worn concrete roadway-andoan asphalt.sur-

'to'lead the asphalt surface coat intoth'e pores. of the concrete roadway and into the crevices of the roughened surface, ap-

plying an asphalt surface coat. mixture to the coated surface and working the asphalt surface coat mixture well into. the roughened surface of the concrete roadway.

ture. p

BERTIN 'MoCAFF REY.

. In testimony whereof "I afiix my signa- 

